Showing All Triangles
To make all triangles visible, select "Elevation Grid" -> "Unhide All Faces".

Specifying Color of the Elevation Grid
You can specify color of the elevation grid by choosing color with Color Dialog, and selecting "Elevation Grid" -> "Paint All Faces".

Adjusting Triangulation
You can adjust triangulation so that the elevation grid will have less unnatural unevenness by selecting "Elevation Grid" -> "Apply Delaunay Triangulation".

Applying Color Gradation Based on the Elevation
You can set color gradation based on the elevation by selecting "Elevation Grid" -> "Apply Color Gradation". You can specify the color at the peak and at the foot of the elevation grid by the dialog shown below.

If you choose to apply color gradation, the color specified by Paint All Faces will not be shown. If you want to remove color gradation and use the color specified by Paint All Faces, select "Elevation Grid" -> "Flip Gradation Flag".

(Selecting colors at the peak and foot of the Elevation Grid)

(Example of gradation)

Showing/Hiding Side Walls
You can make side wall of the elevation grid by selecting "Elevation Grid" -> "Show/Hide Side Wall".